1. Charge It!
Cross-Curricular Focus: Physical Science
Many people do not really understand how electricity works.
They just know that when they need power to run an appliance, they
have to plug it into the wall.
Energy comes from charged particles that are moving around.
Have you ever rubbed a balloon against your clothes to make it
stick? Have you held a balloon or a comb over someone’s head to
watch his hair stand up straight? That’s static electricity and
electrically charged particles. But these particles don’t do much
unless we control their energy.
Static electricity builds up on certain materials. Other materials,
though, let electrical charges fl ow through them. This creates an
electric current. Electric current travels very easily through metals like
copper, gold, silver, and aluminum. We call materials that electric
current fl ows through easily conductors. Water is also a good
conductor of electricity. That’s why electrical charges can travel
through people, too. There is water in every cell of a person’s body.
Electric current can travel through these cells.
Since metal is a good conductor of electricity, elec trical wires are
often made out of metal. Wiring can also be made out of non-metal
materials, such as graphite.
Conductors have to be enclosed in a material that is an insulator
Insulators do not allow electric current to pass through them. The
rubber coating that you see on electrical cords covers the metal.
The electric current stays inside the cord so we can direct the
current to the appliance that needs power. Other good insulators are
glass and some plastics.
Cross-Curricular Reading Comprehension Worksheets: D-20 of 36
Name:
Answer the following questions based on
the reading passage. Don’t forget to go back
to the passage whenever necessary to fi nd
or confi rm your answers.
1) What are two materials that are good
conductors of electricity?
2) How is static electricity different
from electric current?
3) What could happen if the rubber
coating on a power cord is damaged?
4) Is water a conductor or an insulator?
5) In your own words, explain the difference
between a conductor and an insulator.